<?php

/**

 * Yab Framework

 *  

 * @category   Yab_Db_Adapter

 * @package    Yab_Db_Adapter_Abstract

 * @author     Yann BELLUZZI

 * @copyright  (c) 2010 YBellu

 * @license    http://www.ybellu.com/yab-framework/license.html

 * @link       http://www.ybellu.com/yab-framework 

 */



abstract class Yab_Db_Adapter_Abstract {



	const DEFAULT_ENCODING = 'UTF-8';



	static private $_default_adapter = null;



	private $_columns = array();

	

	private $_schema = null;

	

	final public function __construct() {



		if(!self::hasDefaultAdapter())

			self::setDefaultAdapter($this);

	

		$args = func_get_args();

			

		Yab_Loader::getInstance()->invoke($this, 'construct', $args);

	

	}

	

	public function construct() {}

	

	abstract public function setEncoding($encoding = self::DEFAULT_ENCODING);

	abstract public function isConnected();

	abstract public function _quoteIdentifier($text);

	abstract public function fetch($rowset);

	abstract public function free($rowset);

	abstract public function limit($sql, $from, $offset);

	abstract public function getSelectedRows($rowset);

	abstract public function getSelectedSchema();

	abstract public function getTables($schema = null);

	abstract public function _columns($table);

	abstract public function formatTable(Yab_Db_Table $table);



	abstract protected function _lastInsertId($table);

	abstract protected function _disconnect();

	abstract protected function _setSchema($schema);

	abstract protected function _connect();

	abstract protected function _error();

	abstract protected function _query($sql);

	abstract protected function _affectedRows();

	abstract protected function _quote($text);



	final public function setDefault() {



		self::setDefaultAdapter($this);



		return $this;



	}



	final public function quote($text) {



		if(!$this->isConnected())

			$this->connect();



		return $this->_quote($text);



	}



	final public function quoteIdentifier($text) {



		return $this->_quoteIdentifier($this->unQuoteIdentifier($text));



	}



	final public function getAffectedRows() {



		if(!$this->isConnected())

			$this->connect();



		return $this->_affectedRows();



	}



	final public function getLastInsertId($table) {



		if(!$this->isConnected())

			$this->connect();



		return $this->_lastInsertId($table);



	}



	final public function disconnect() {



		if(!$this->isConnected())

			throw new Yab_Exception('can not disconnect from db server, no connexion');



		$this->_disconnect();



		return $this;



	}



	final public function setSchema($schema) {



		$this->_schema = $schema;

	

		if(!$this->isConnected())

			return $this;

		

		$this->_setSchema($schema);



		return $this;



	}



	final public function connect() {



		if($this->isConnected())

			throw new Yab_Exception('already connected to the db server');



		$this->_connect();

		

		if($this->_schema)

			$this->_setSchema($this->_schema);



		return $this;



	}

	

	final static public function hasDefaultAdapter() {



		return self::$_default_adapter instanceof Yab_Db_Adapter_Abstract;



	}



	final static public function setDefaultAdapter(Yab_Db_Adapter_Abstract $adapter) {



		self::$_default_adapter = $adapter;



	}



	final static public function getDefaultAdapter() {



		if(!self::$_default_adapter)

			throw new Yab_Exception('no default db adapter defined');

	

		return self::$_default_adapter;



	}



	final public function getError() {



		if(!$this->isConnected())

			$this->connect();



		return $this->_error();



	}



	final public function query($sql) {



		if(!$this->isConnected())

			$this->connect();



		Yab_Loader::getInstance('Yab_Observer')->notify('SQL_QUERY', array($sql));

		

		$sql = rtrim($sql, ';');



		$rowset = $this->_query($sql);



		if(!$rowset)

			throw new Yab_Exception($this->getError());



		return $rowset;



	}



	final public function __destruct() {



		if($this->isConnected())

			$this->disconnect();



	}

	

	final public function resetColumns($table = null) {

		

		$table_name = (string) $table;

		

		if($table_name) {

		

			if(array_key_exists($table_name, $this->_columns))

				unset($this->_columns[$table_name]);

				

		} else {

		

			$this->_columns = array();

		

		}

		

		return $this;

	

	}

	

	final public function getColumns($table) {

		

		$table_name = (string) $table;

		

		if(array_key_exists($table_name, $this->_columns))

			return $this->_columns[$table_name];

	

		$this->_columns[$table_name] = $this->_columns($table);

		

		return $this->_columns[$table_name];

	

	}



	final public function getTable($name, $schema = null) {



		if($name instanceof Yab_Db_Table)

			return $name;



		try {



			if($schema === null)

				return Yab_Loader::getInstance()->invoke($name, array($this), 'Yab_Db_Table');



		} catch(Yab_Exception $e) {}



		$name = $this->quoteIdentifier($name);

		$schema = $this->quoteIdentifier($schema);



		$key = $this->unQuoteIdentifier($schema.'.'.$name);



		return new Yab_Db_Table($this, $key);



	}



	final public function prepare($sql) {



		return new Yab_Db_Statement($this, $sql);



	}



	final public function insert($table, array $values) {



		$table = $this->getTable($table);



		foreach($values as $key => $value)

			$values[$key] = $value !== null ? ($table->getColumn($key)->getQuotable() ? $this->quote($value) : (is_numeric($value) ? $value : 'NULL')) : 'NULL';



		$this->query('INSERT INTO '.$this->quoteIdentifier($table).' ('.implode(', ', array_map(array($this, 'quoteIdentifier'), array_keys($values))).') VALUES ('.implode(', ', $values).')');



		return $this->getAffectedRows();



	}



	final public function update($table, array $values, $where) {



		$table = $this->getTable($table);



		foreach($values as $key => $value)

			$values[$key] = $this->quoteIdentifier($key).' = '.($value !== null ? ($table->getColumn($key)->getQuotable() ? $this->quote($value) : (is_numeric($value) ? $value : 'NULL')) : 'NULL');



		$this->query('UPDATE '.$this->quoteIdentifier($table).' SET '.implode(', ', $values).' WHERE '.$where);



		return $this->getAffectedRows();



	}



	final public function delete($table, $where) {



		$this->query('DELETE FROM '.$this->quoteIdentifier($table).' WHERE '.$where);



		return $this->getAffectedRows();



	}



	final public function truncate($table) {



		$this->query('DELETE FROM '.$this->quoteIdentifier($table));



		return $this->getAffectedRows();



	}



	final public function unQuoteIdentifier($text) {



		$text = preg_replace('#^[^a-zA-Z0-9_\-]*#', '', trim((string) $text));

		$text = preg_replace('#[^a-zA-Z0-9_\-]*$#', '', trim((string) $text));



		return trim((string) $text);



	}



}



// Do not clause PHP tags unless it is really necessary